The present invention relates to a mounting device for mounting push-button switches and other switches or the like on a panel plate or the like. In general, a conventional mounting device of this type uses elastic elements as disclosed in U.S. Pat. No. 4,268,735. However, it is required, depending on the use, that a switch or the like is not mounted on the panel plate or the like with elastic elements but is instead mounted with screw threads. Thus, a mounting device which employs screw threads is required. However, it is inconvenient for both manufacturers and users to separately manufacture two kinds of mounting devices which are different in the mounting system. In this connection, it has been desired to develop a mounting device for a switch or the like, which can overcome such an inconvenience and can be used by suitably selecting one of the two systems.